CHEM 1120 1st EditionExam # 1 Study Guide Lectures: 1 - 11Lecture 1 Vocabulary or Concept Definition or ExplanationSolvent Majority of a solution, what substance is being dissolved inSolute Least part of a solution, what is being dissolvedSolvating Solvent pulling the solute particles apart, how a solution formsIntermolecular Forces Forces between different moleculesSolutions will only formif…Solution of A and B will only form if A-B attractions are comparable in strength to A-A and B-B attractions, if not they won’t mix (i.e. water and oil)Ion-Dipole force Strongest intermolecular force, ion and dipole interactHydrogen bonding Hydrogen bonds to N, O, FDipole-dipole 2 dipoles interactingIon-induced dipole Bring a charge next to something that doesn’t have a dipole, causesit to become a dipole. Take charge away, dipole goes away. Less common.Dipole-induced dipole Less common, similar to ion-inducedDispersion forces At an instantaneous point, molecule has a charge. Weakest intermolecular force3 steps to substances dissolving (ex. NaCl in water)1. NaCl crystals separate into ions (Endothermic process)2. Water molecules create holes to accommodate Na+ and Cl- ions (endothermic)3. Na+ and Cl- ions enter the holes (exothermic)ΔH of Solution ΔH of solute (+) + ΔH of solvent (+) + ΔH of mixing (-)Unsaturated Add more of a solute to a solvent and it dissolves, less solute than can dissolve in the solventSupersaturated Add more and it crystalizes, solvent hold more solute than is normally possible, very unstableSaturated At equilibrium, most solute that the solvent can possibly holdEquations:ΔH of Solution = ΔH of solute (+) + ΔH of solvent (+) + ΔH of mixing (-)Lecture 2 Vocabulary or Concept Definition or ExplanationSolubility Maximum amount of solute dissolved in a given amount of solvent at temperature T“Like dissolves like” Similar things dissolve, good rule of thumb for solubilityEffect of Temperature on SolubilitySolids: Higher temperature = greater solubilityGases: Higher temperature = lower solubilityHenry’s Law Gas solubility is directly proportional to the gas’ pressure over the solution (Solubility of gas (mol/L) = k (mol/Latm) x Pressure of the gas (atm)Molarity (M) Moles of solute/Liters of solutionMolality (m) Moles of solute/kg of solvent, independent of temperatureMass percent (% w/w) (Mass of component/ total mass of solution) x 100Volume percent (% v/v) (Volume of component/ volume of solution) x 100, need densities to solve equations using thisMole fraction (X) Mole fraction of A = moles of A/ total moles of all components Parts per million (ppm) and parts per billion (ppb)Ppm of component = (Mass of component/total mass of solution) x 10^6Ppb of component = (mass of component/total mass of solution) x 10^9Colligative properties Solution properties that depend ONLY upon the number of the solute particles, not their nature or identity (i.e.- vapor pressure lowering, osmosis, freezing point depression, boiling point elevation)Raoult’s Law (vapor pressure lowering)Pa = XaPoa, where Pa = solvent v.p., Xa = solvent mole fraction, and Poa = pure solvent v.p. Equations:Solubility of gas (mol/L) = k (mol/Latm) x Pressure of the gas (atm)Molarity (M) = moles of solute/ Liters of solutionMolality (m) = moles of solute/ kg of solventMass percent (% w/w) = (Mass of component/ total mass of solution) x 100Volume percent (% v/v) = (Volume of component/ volume of solution) x 100Mole fraction (X) of A = moles of A/ total moles of all componentsPpm of component = (Mass of component/total mass of solution) x 10^6Ppb of component = (mass of component/total mass of solution) x 10^9Pa = XaPoaLecture 3Vocabulary or Concept Definition or ExplanationMore on Raoult’s Law Change in Pa = Xb x Poa, where A = solvent and B = solute, strong solute-solvent interactions  negative deviations from raoult’s lawChange in boiling point elevationTb = Kb x mChange in freezing point depressionTf = Kf x m depend on solvent, not soluteOsmosis Diffusion of solvent through semi-permeable membrane into a solution of higher concentrationOsmotic pressure (Π) MRTColligative Properties of Electrolyte solutionsElectrolytes do not completely dissociate, use Vant Hoff Factor: Van’t Hoff Factor = i = Change in Tf (measured) / Change in Tf (expected for nonelectrolyte)Suspension Heterogeneous mixture with dispersed particles large enough to be seenColloid A mixture with dispersed particles larger than a solution’s, but smaller than a suspensions (Ex. Fog/clouds, butter, marshmallows, paint, whipped cream, milk)Tyndall Effect Colloidal suspensions can scatter rays of lightHydrophilic colloids Water loving, easily dispersed in waterHydrophobic colloids Must be stabilized by ions absorbed on the particle’s surface or by hydrophilic groups in the particle’s surfaceEquations:Change in Pa = Xb x PoaTb = Kb x mTf = Kf x mΠ = MRTVan’t Hoff Factor = i = Change in Tf (measured) / Change in Tf (expected for nonelectrolyte)Lecture 4Vocabulary or Concept Definition or ExplanationReaction Rate –1/a(ΔA/Δt) = -1/b (ΔB/Δt) = 1/c (ΔC/Δt) = 1/d (ΔD/Δt), Where reaction is aA + bB  cC + dD, measured in units of concentration per time (i.e. M/s)Rate law Rate = k x [A]^m x [B]^n, Where reaction is aA + bB  cC + dD, m and n are order of the reactionFactors the affect speed of a reactionReactant physical state, reactant concentration, temperature, catalystsAverage Rate vs Instantaneous RateRate of reaction averaged over a period of time vs. rate at an arbitrarily short time (at a particular point in time) (tangent tocurve)Units of rate constants Units of rate = (units of rate constant)(Units of concentration)^orderEquations:–1/a(ΔA/Δt) = -1/b (ΔB/Δt) = 1/c (ΔC/Δt) = 1/d (ΔD/Δt),Rate = k x [A]^m x [B]^nUnits of rate = (units of rate constant)(Units of concentration)^orderLecture 5Vocabulary or Concept Definition or ExplanationMethod of initial Rates Determine reaction orders from the effect of changing a reactant’s concentration on the initial rate of the reactionHow to calculate rate orderRate 2/Rate 1 = [A]^n x [B]^m x [C]^p (for rate 2) / [A]^n x [B]^m x [C]^p (for rate 1), solve for m and nIntegrated rate laws 0th order: [A] at time t = -kt + [A] initially1st order: Ln[A] = -kt + ln[A] initially2nd order: 1/[A] = kt + 1/[A] initiallyConfirming 1st order reactions using concentration vs timeGraph should exponentially decay, graph t vs ln [A], linear  first order